This invention relates to an optical pickup for optically reproducing information recorded on a recording medium or for optically recording information onto the recording medium, and more particularly to a pickup for reproducing information recorded on an optical disk used for a compact disk (CD) player, a lazer vision disk (LVD) player or the like.
As a conventional optical pickup, there has appeared an integrated-optic disk pickup (IODPU) lately which comprises a semiconductor laser for emitting a laser beam, located on one side of a semiconductor substrate, an optical condensing grating coupler for diffracting the laser beam, located on the other side thereof to irradiate an information recording surface of the optical disk with the laser beam, and a beam splitter for splitting a beam reflected from the information recording surface into two beams to guide them toward two photodiodes, respectively.
In the above conventional pickup, the optical condensing grating coupler must function to diffract the beam emitted from the semiconductor laser to condense it concisely onto a specified point on the disk. Accordingly, the structure of the condensing grating coupler is complicated so as to achieve the required position.